1. Field of the Invention
The present invention relates to an image sensor and a sensor unit, and more particularly, it relates to an image sensor and a sensor unit each comprising a region for increasing the number of signal charges.
2. Description of the Background Art
In general, a CMOS image sensor comprises a photodiode for photoelectrically converting incident light to electrons, an electrode for reading electrons stored in the photodiode and a floating diffusion region for converting the stored electrons (signal charges) into a voltage signal.
In relation to this, a method of increasing (multiplying) the number of the electrons by impact-ionizing the stored electrons in order to improve sensitivity is conceivable. When this method of increasing the number of the electrons is employed, various examinations are required.